I've heard people state from time to time that it is foolish of Christians to believe that God actually 'lives' inside of them. "Is there a hole or something down in there where He stays?" is how I believe I've heard it phrased.
Granted, this is an odd thing. While the Bible clearly states that the Spirit of God lives or dwells inside us ....
John 14:16-18 And I will pray the Father, and He will give you another Helper, that He may abide with you forever—the Spirit of truth, whom the world cannot receive, because it neither sees Him nor knows Him; but you know Him, for He dwells with you and will be in you. I will not leave you orphans; I will come to you.
1Corinthians 3:16 Do you not know that you are the temple of God, and that the Spirit of God lives in you?
... it is obvious to us that there isn't a specific place or location within us where He resides. So how do we explain the biblical statement that God can actually reside within us?
Let's look at it from a different viewpoint (for readers of C.S. Lewis, you'll recognize this analogy from his book "Mere Christianity"). Let's say that we were scientists and we came to this planet to observe life here. We would observe a various assortment of things like electricity, lettuce and dogs. Now as scientists, we can only learn from what we observe. We can't get 'inside' of the lettuce or the dog to know what is going on. Whether they have a mind, whether they can think or reason, whether they have morals ... we can only infer those things from watching their actions.
But when it comes to humans, it's a entirely different story. We can learn not only from observing their actions, we also get an entirely different viewpoint because we are human! And when I look inside myself, I see something that I absolutely cannot explain. I see that I have a spirit. That spirit feels emotions and it thinks and it plans and a million other things. But where does it live? Where does it dwell? How can it even exist inside of me when I'm only made up of blood and tissue and fluids?
So can I explain how the Spirit of God lives inside of me? No, I can't. But I also can't explain how my own spirit lives inside of me, either. And when I look at it from that perspective, it doesn't seem that odd at all that His Spirit can dwell with my spirit .. wherever that may be.
Ecclesiastes 11:5 As you do not know the path of the wind, or how the body is formed in a mother's womb, so you cannot understand the work of God, the Maker of all things.